Re: [Exim] Multiple recipients and whitelist checks

On Fri, 16 Jul 2004, Tony Finch wrote:

> On Fri, 16 Jul 2004, Alan J. Flavell wrote:
> >
> > This sounds like a variant of the question about multiple spam
> > acceptance policies. Our method is based on selective defer. If
> > you've only got two different policies to implement, there's no
> > need to force it down to one recipient per transaction: you can
> > accept the mail in just two batches.
>
> What kind of delays does this cause?

To be honest, I don't maintain those kind of numbers routinely; but I
took a look at the log anyway.

Looking at the log, it seems that the second batch is completed within
typically 6 to 20 seconds of the first. Sometimes the offering MTA
passes the second batch off to our backup MTA, sometimes they retry it
directly themselves, but in either case the final delivery seems to be
complete within tens of seconds. That's discounting the senders who
didn't bother to retry: but a mere glance at the envelope-sender
addresses etc. makes it clear that they were spammers.

I'm a bit surprised by how quickly it happened. I wound't have been
surprised if some offering MTAs had delayed by up to around 15mins
before retrying; that would have been fine by me, what say you?

[...]
> This implies quite a lot of deliveries for a message with lots of
> recipients, and possibly delays of hours.

I suppose there might be cases where that happens, but on this sample
it seems it's not the most likely outcome. Possibly the best numbers
for your purpose would come from someone who's set their MTA to accept
only one RCPT per transaction, and defer the rest?